Did you know? A bicycle is a marvel of engineering efficiency, one where an investment in 22 pounds of metal and rubber boosts the efficiency of an individual mobility by a factor of three. On my bike I estimate that I get easily 7 miles per potato. For more information view the text and data in Chapter 6 of Plan B 4.0: Mobilizing to Save Civilization.

Chapter 2. Stopping at Seven Billion: A New Demographic Era

Nearly 3 billion people are expected to be added to our world during the first half of this century—slightly fewer than the 3.5 billion added during the last half of the twentieth century. There are some important differences in these numbers, however. Whereas the growth in 1950–2000 occurred in both industrial and developing countries, the growth in the next 50 years will be almost entirely in the developing ones. Big additions are projected for the Indian subcontinent and sub-Saharan Africa, which together will account for nearly 2 billion of the 3 billion total increase. 5

As noted, populations are projected to shrink in some developing countries, but for the wrong reasons. Whereas the populations of Russia, Japan, and Germany are projected to decline by 2050 by 30, 13, and 3 percent, respectively, due to falling fertility, those of Botswana, South Africa, and Swaziland are expected to decline by 43, 11, and 2 percent because of rising mortality. Are these three African countries an aberration or are they merely among the first of many countries where HIV/AIDS, spreading hunger, the loss of water supplies, and possibly civil conflict lead to rising death rates and population decline? 6

Another major shift will come as record variations of national population growth and decline redraw the world demographic map. A comparison of the 20 most populous countries in 2000 and those projected for 2050 illustrates these changes. (See Table 2–1.) To begin with, the two largest countries—China and India—will trade places as India’s population, projected to grow by over 500 million by 2050, overtakes that of China sometime around 2040. 7

In the four most populous industrial countries after the United States—Russia, Japan, Germany, and the United Kingdom—populations are projected to be smaller in 2050 than they are today. Indeed, only Japan and Russia will remain among the top 20 by mid-century. Germany and the United Kingdom will drop off the list, as will Thailand, a developing country that is approaching population stability. 8

The three countries on the list with the greatest growth, with each expected to more than double by 2050, are Pakistan, Nigeria, and Ethiopia. The three newcomers on the top 20 list in 2050—the Democratic Republic of the Congo, Uganda, and Yemen—are each projected to triple their populations by mid-century. 9

What these demographic projections do not take into account are the constraints imposed by the capacity of life-support systems in individual countries. In many cases, the projection clearly exceeds the country’s apparent ability to support its population. For example, the notion that Yemen—a country of 21 million people, where water tables are falling everywhere—will one day be able to support 84 million people requires a stretch of the imagination. Is Pakistan, with 158 million people today, likely to add nearly 200 million by 2050, making it larger than the United States today? And is it really possible that Nigeria will have 258 million people by 2050—almost as many as the United States has now? 10

Table 2-1. The World's 20 Most Populous Countries, 2000 and 2050

2000

2050

Country

Population

Country

Population

(million)

(million)

China

1,275

India

1,531

India

1,017

China

1,395

United States

285

United States

409

Indonesia

212

Pakiston

349

Brazil

172

Indonesia

294

Russia

146

Nigeria

258

Pakiston

143

Bangladesh

255

Bangladesh

138

Brazil

233

Japan

127

Ethiopia

171

Nigeria

115

Dem Rep of the Congo

152

Mexico

99

Mexico

140

Germany

82

Egypt

127

Viet Nam

78

Philippines

127

Philippines

76

Viet Nam

118

Iran

66

Japan

110

Egypt

68

Iran

105

Turkey

68

Uganda

103

Ethiopia

66

Russia

102

Thailand

61

Turkey

98

United Kingdom

59

Yemen

84

Source: See endnote 7.

NOTES5. United Nations, op. cit. note 1.

6. Population projections for Germany, Japan, and Russia from United Nations, op. cit. note 1; Botswana, South Africa, and Swaziland from PRB, op. cit. note 2.